Research Progress on Regulation of Bacterial Exopolysaccharide Biosynthesis by Cyclic Diguanylate

Bacterial exopolysaccharide (EPS) is a secondary metabolite that is synthesized and secreted outside the cell wall during bacterial growth and metabolism. It can regulate the initial attachment of cells to different substrates and protect cells against environmental stress and dehydration. As a potential prebiotic, EPS has the characteristics of safety, non-toxicity and unique physical and chemical properties, and is widely used in the fields of food, medicine, biology and industry. However, the bacterial metabolic system is complex, and the biosynthetic mechanism of EPS has not been fully elucidated. Cyclic diguanylate (c-di-GMP) is an important second messenger, and it plays an important role in the regulation of many physiological activities such as biofilm formation, motility, adhesion, virulence and EPS synthesis. The analysis of the transcriptional regulation mechanism of c-di-GMP provides a new idea for exploring the biosynthesis mechanism of bacterial EPS. This paper summarizes the characteristics and synthetic degradation pathways of c-di-GMP in detail, and focuses on the regulatory mechanism of c-di-GMP in the process of bacterial EPS biosynthesis. This paper provides a theoretical basis for revealing the mechanism of bacterial EPS biosynthesis and the structure-activity relationship.